This invention relates to a temperature, pulse and respiration detector. More particularly, this invention relates to a combined temperature, pulse and respiration detector in which a patient's temperature can be sensed simultaneously with his pulse and respiration rates.
It is well known to use a temperature sensor such as a thermistor to sense temperature or to detect respiration. It is also well known to detect pulse rate using the photoelectric measurement of changes in the radiation transmission characteristics of tissue through which blood is circulating. One photoelectric method of pulse rate detection is disclosed in U.S. Pat. No. 3,139,086.
Techniques have been only recently developed for simultaneously sensing temperature, pulse rate and/or respiration by means suitable for economic wide spread use, as for instance, in hospital wards. These known temperature, pulse and/or respiration detectors comprise a disposable probe with a thermopile mounted thereon and are disclosed in commonly assigned application Ser. No. 409,637, filed Oct. 25, 1973 for TEMPERATURE, PULSE AND RESPIRATION DETECTOR, by Douglas G. Noiles, one of the co-inventors herein. These detectors represent a marked advance over the state of the art but have some disadvantages including the mounting of the temperature and/or respiration sensors on the disposable probe. For reasons of economy, it would be desirable to have a detector for simultaneously detecting temperature, pulse and respiration in which the sensor is non-disposable and adapted to associate with a disposable cover so that the sensor can be used in a hygienic manner.
It is known to determine respiratory activity by detecting the flow of air through the nostrils. A typical pneumograph employs a thermistor placed in the outer nasal passage to detect the temperature change of the thermistor due to the cooling effect of the flow of inspired and expired air. It is also known to place the thermistor in the mouth or in a position to detect flow from either the nose or the mouth. However, if the thermistor is placed in the outer nasal passagge or mouth, the thermistor cannot be re-used without being sterilized. Accordingly, there is a need in the art for a detector for detecting the flow of respiratory air which is reusable without being sterilized after each use. Furthermore, a suitable detector is yet to be developed for housing the respiration sensor and for directing air flow to the sensor.
Known methods and apparatus for photoelectrically measuring the pulse rate by detecting changes in the radiation transmission characteristics of blood carrying tissue such as disclosed in U.S. Pat. No. 3,139,086 employ a detector in which the patient's thumb, for example, is placed over the end of a detector containing a suitable light source and photocell. In these devices, no provision is made to avoid the transmission of bacteria from one patient to another, nor is the apparatus adapted to be used for the simultaneous detection of oral temperature, pulse and respiration. Accordingly, problems of hygiene may arise in a hospital environment from the use of these devices and their applicability is limited.